SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f45b1fff61bdd039904b520218c41293b5edca92e2a5b90d157bdcc015ebf44' 
  AND token = 'YW8daZbMMU0kRLbKX8i3VlZWgTYZ+blQl1akWlKbzY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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