SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '236fc9f8351448f79660a2bc71bfae6bf8fb045225d2bc2220b0a3b78da4edb4' 
  AND token = '4lPmadlwXTjUPLgGAYrrC5HNbzKH5y901ZYnzIWleTE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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