SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0671ff5c3c6936a9daea41cfd0e9937f0d19b760576b70b3d3f6eaefabf9603e' 
  AND token = 'pXU8moKzPFGI3KsKN+ghdY4QauQcNMWl+falPkBwbiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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