SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8423bffcb3ab1e2ae952fc8b0dd16ff0afd682d232c176871b7679dcb4e054a' 
  AND token = '1JYAhZK1nPtvw+3++iNjAtpeVcyXPqWBTgayKRrEtKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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