SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1a1c5c5617e9046661c97b60a1cef7d122ec58926abbd0038ff33dddcec6db4' 
  AND token = 'DyiGG9uYZnBuE1h+gxa3UvvRKTWZjeKgUoISelmWQ+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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