SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ca104588b80da0d59a3790679248605929524998d9a2d9ad7ed5ce5c73821c87' 
  AND token = '97Z17qTqOwAAdfveJ302v1inHMUIBHbmuCO0jiBJUDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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