SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b15ed7743b1b6c114f97dfcc7b5b2c64470b0877874e8c8611ad12c5756668c7' 
  AND token = 'WpsjH0joRucPdAlGhD5hQM0oyJtfCRryzHcHoovsoJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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