SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '858b0a02265b87d375a61a7318f981fa39959d47a81fb8014d67c36ebac08eef' 
  AND token = 'kLYRfdzYTBXoHWTwKZxkvu4qY5hsKO3HkNa66/ahToQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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