SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6754933c711e881b597cb1c2cdf2f380c714afc5c0bff1d1ca58290a652353a' 
  AND token = 'YzDTcN13dFsCcj+VefR+buIWuLR8UKRYce/WbwrM4IY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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