SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fac4549b6d6acf252595d43c9bc3a783ad63b95543fd8e78daed2876dc98e14' 
  AND token = 'rAQB+aIFgamWWpxRxK6+CxL1GV4RDwdpyMoqK1PHxoo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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