SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '80d91141525e754d734a3d3f241378723492c4342fe3037234d91fe5954ecd3a' 
  AND token = '9gpNKFNzpMxtWZvxsPIPicKG1zoJ3eWytG+OknOb+fk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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