SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c7fd9b5610088039a7bf507aa8f63da6b972483fc7ad2c8720c757944e8a889' 
  AND token = '/xVIkE9x/3yxNI/MC5C9ty1+5MT8D7X0QvO9eAvnduw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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