SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '554f33f58bb2ed06995971157bab7d1840d5da61da7accc32665dce9716af42c' 
  AND token = 'IBmEfXdEsg0qrJMu4cXByuVopQjg0jn+Hszg/RJ/Gvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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