SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98161e29673b21f1ec3deee12a3a98004f2ec9791f520101a977b4355943b593' 
  AND token = 'SOcbuQvEbqqzpLVg5G+/XI4oGDuMWrj6koaaVhR6FK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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