SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03fb6d8883f1150660bc33704e8b0eb6e3e4037425ef847424167d97a195d97a' 
  AND token = 'B6WxIQFUQqzSlf3RBb7BHg4vtLnvfTexnNqRubS7gDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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