SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '864a9f420350e8f1872d442987df314723e47f3d48d6fc8ea7996293cd4f5270' 
  AND token = 'LLVL1HonPyxItfNhA1JgbG9OeZ72SQH8mli+LL7V4fU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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