SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '192f103554e82fe8017fff4df7719ad9d3a20b4f9379301689a54c2d6e6b84b7' 
  AND token = 'uc8UTjqj+iFCC9UnCSPRhNqMKXc3QZGgtaTsC9L2b4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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