SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a7feaecb09362a7da5b323b55de56b3f836212e311f2c9d8825d72e8a704a59' 
  AND token = 'LwfhmD79ZdEgB3PnZQcpARo7JxZgDBmjPLUrO0FgD+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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