SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d67ba3f91e2fe314c8de933f076c4887236597272bc4d52055a14da1abd2b87' 
  AND token = 'j7YcaBVrhvS+gdk0gT+VFiBHj7ZgTRn//fGKwokoR4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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