SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03ef8543a4bb5ddccd957b5c1c56e1f902de6a63087b610ce426a19d1df0ec8a' 
  AND token = 'lFDLkhyJ5/e99PfkKrFMYC27cbJR0Rp4CbaYJpqHsMA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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