SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f88de594cc672d93f3c6486f644a83d8a05c64ab321e918452224bbfef81035' 
  AND token = 'h3E5iPpqUSc/+oyr/CgIPKrMVvwjsQGUk3GmVlZVHb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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