SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99d257a8389f1363b587af2c16cdb216b9418e741d70b4378d2a2c8639f06da6' 
  AND token = 'crh0jVHrS0K3gxZOBrULTVHlFsQ4CDjEPZbF3Dxyh8M=' 
  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"
    }
  }
}