SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4fabbe74bb56582c296ea12481281e4f50d16c9a82ecfbc7449299f37702567' 
  AND token = '5rTsDQmF04Z1n0izBKIO5gpgryG8gMz6wURrl0BHKd0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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