SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5549911cf89f1bf16c65d3f1f5242eb6c4973ea3de60d94b1a8dfc9d5670516e' 
  AND token = 'yJQBeIQ8k588TIebmLXQdyvsQYIhPeFSMdy56TmzoAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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