SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20f79522578561dcf8fb2fccc9bf2f1be79e11f1ec0121df8be3c48a95d881b1' 
  AND token = 'QXmrL6h4B7QpVmYRviFPFiaPFPgmAjTZv73r11MOfqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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