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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c7bdd76235db6357fb6df36fca8238d87b01c49d8bd3bafe5fb4263d085fe51' 
  AND token = 'jo0EKMgOuCrcIqr03I9vmBUfYkrDpwt8TddS7FXTZ18=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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