SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '540249f9f0936224a343c9f311fdf66effbaca9d7e5adbe8f2e6588bdbaf583e' 
  AND token = 'UgHP4bPnzRbDqdyI9pTmvfQ+9bGsXhgoR8gGfrWC7IY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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