SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c87c68554fba58ade2310bfe7634c5841d4074963d5e6ad627b25d93dca9783' 
  AND token = 'Y8SP/X0DwzxqRnXHAbD0iRjuJGFgOr1T/dzJZOvT5eA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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