SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af2263f9fecdced21a05245ea5a825a3a38ba7b8d9d69467d7ea74c934b66c03' 
  AND token = 'zH5Es11h/su0qZBiuI8NitQ9NyBPVNFThDLT6BJB5Yg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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