SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c8a8542f8d6fbd7e6aff908190267bf05f636aa7b594df12a507e8493df766c8' 
  AND token = 'g39wXU57pj7bdZW8t7MGlKjP9+SWqV1xTkCggVEewG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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