SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '335740774d117b1288b0e6c29a9d027d25036e8ef1dcf150816426a043c5937c' 
  AND token = 'JmT2zX25Knq2vQnboO6/ejChxJP/uMh6zQH7IwXk+2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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