SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd49e6bc8154ba21a596dcee5b2422e153ff337083d720def5859c9c140c83cfb' 
  AND token = 'KY4ZdcDNFCHgrHcLYE5Wl2qN/cuClTD79C+rtxFbHAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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