SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5df996b6c735f1e58f55bf4fdd3356f72a2746a4cc8a8ae9053b3e9196b42ae6' 
  AND token = 'O6GfdGjC4hgtXO7rj6nhEl2+mAwM/WYvnqgRvRwmtIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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