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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd56f7b1351e73efcf1d0ef1d71b216d7cf870ac642c39290d7aa6f6e6a11e7b' 
  AND token = 'Zuf0cmkOc3TVOCtZhDj58Ag1X3xoewmBlwvp3abA2ZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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