SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e356ef9c77f0701fbbbb7c5baf3e546609279545dfc4b0b6f570c0d6901dbe00' 
  AND token = '5KgSXEZ15N+YV+2mi/UlewSl21hATWK6girJTMoP1jQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}