SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62eeaa6a41f3b1b9b6166cfa48df187c7cd42046ac4bb963efd1243524844c1d' 
  AND token = 'kt7utIUvjRoKihZk7QH48ynUVkAOZrhFdUbU4A/kMC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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