SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4d19962a002a93215a0b5b3cf8fec15f469b26139f46c5e0883b56431681909' 
  AND token = 'ZxjBO2b9YBQoUSUZq//kkbnkDV/uud12YEqEaIC7Oq0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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