SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45686327548ba9dc025a5291e7dfd0f0d558a5bee7fac4bbd3e81220dc56474b' 
  AND token = 'ohwF1ypmqVa2+RY6IX6Y76zJsVLiWUyRBS7/VbvD9Wo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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