SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57cec0b5f983d4f52f8d89ffc7d87c620032fbba93c0538f3cd70975f5e3d104' 
  AND token = 'siUg7Hu0KlNZQHjhl1CT996/2gpvLIYE5MlXYDy5jVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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