SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '879c48d19852a9c8c3864e536fa9b0ae336b579d2faab40949e168c13cf28386' 
  AND token = 'FgokaWwCE4YzdOALYgqGlHtMId2ONfbk/vigQo2vFmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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