SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b02c2fdd36ed059bee62eac64d203826f4f3d1ca37f5afa0fa7a34840a1e1c65' 
  AND token = 'nhO3KKSuSJrjykPoNXWpYwIguyPyCXICiWG0wRbnn2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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