SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0bcd70a67988185b5d8f5afc4d21e703754369ec6a50d0ba506e38d2639694d8' 
  AND token = 'lDZUIDxXtXntM/v148Huqc7tK+U2wYchw5Ap/TZ5KgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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