SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a7fc48d5a109206b34d5a14eb2ba21658510c64a8552b07f2e2fbf9a41634b73' 
  AND token = 'KJXmc10SdV7foFExo00HkdWhqvi9jtIotV8tTz0j86E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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