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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1bbfe1d525027c9f11a5255bb3fae1beb3e11cbf851db826947c5dd5a61a121' 
  AND token = 'Cb4sCmK9fb7jFUiUJ7qxBnutUNKMnlokCtVYfhoC8Qs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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