SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6feca7afc1435425033553be79320317a28d32d6f2b317c62bc8c8d515d92157' 
  AND token = 'NKSelD1GBGXxCBAMxT7Gab5wA1zEIce4e1uEXsD+J38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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