SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4709df1680a6d99836ecc7077d64b87a697a7923ec93f062d6f562923937a22' 
  AND token = 'm/8ZSuhUYUhoIjxVaRujXYlalYhjYXup0Nlo2ftZL7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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