SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '875081975392f36226607cb3d5895bc765b34ff40156ca53b9104fcad78e9474' 
  AND token = 'ynexx3V1IuTS1jC9qeffjAdcgmOGvDB2iJ4Lof6/KWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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