SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84e28b74dca67ee15c2a20b1075bd5468ff26ac9cdf02be29bb507033e247275' 
  AND token = 'WP2pRbUZtHoX9IzGeseqDtI87DiniAr+kfCezaLmZGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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