SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fedb1166da11eb4500b046079a2950c7769e6658ee798047bfc9e0c27e8ea3c1' 
  AND token = 'W8KyjThKA8XrXRYqtHA+HcjPzoWgvxVbc764aWRV0tA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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