SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f92797b17188c18d50df3ced997ad387d4d90cc402e28562312b269621adf643' 
  AND token = 'X2I8vJhRCriEDIPYvevwRJz2CZhQmkbtWkj1Zqo8uug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}