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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'deb286ecc16f6660f7b4e3951d550d141e8fd2b2a0d4f924ec4be97ee2170f11' 
  AND token = 'g4AuEkrw4f6c9yh0wBOwWGrPnLJy0BFYZSWLg1Ski8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}