SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a27e06bdbf627fd5fd008fb7d8ea1853c596c69214ef90a69a5b0fec8fce7be' 
  AND token = 'g+oSVrOPjlVzQy4jybeCqKsSUOA0uzWZgc3YltF2Y5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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