SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f636b7863c70edc1199218b2f4014d8f301260024e3268dc8de2a1aff3e36119' 
  AND token = 'QRUT/V/7qsmCDqopgBevusWNB2fIzlinXEvlEz1gRYE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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