SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63210c74a2fcc7b777eb1fe33dfe20e1228f9bf4915aa8b5d057508f2e60ca43' 
  AND token = 'e1wlBDj6iEaqmKnfdvgB+e+LC3HlzFTAr6A4vVvHqoM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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