SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2c5932ac71025d92abffd268f35422a0c70e26f3b2a653033b8125260fa0833' 
  AND token = 'dRx1XKF7C/tgM6UdXFGEJBXa9wVtEW7vUYvSjP0KYqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00073

JSON explain

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