SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '010099a804d14e9ffc8cbc65525f1a660c174e67746281cbccc63a20beb76401' 
  AND token = 'DUnlGISjMQPiscded78shnTtZBHi96z59AOLomBQrWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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