SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ec816ef8341b76eef649541eb0e5e97bdd29960445bd2575002f2cffd7ec2d0' 
  AND token = 'EmXX62oa/BYMj2u/DhxHZYhJoO6DmT6qKXSAGg29FrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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