SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '914bac7f5062b43e6fe5c2613d3c50d8a33a258b801937cdc37904ad5e3636b5' 
  AND token = 'ERKzanYmXs/nCoCJdHzYRbY+ZcZIEwYvvR/PsAH0qy8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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