SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3ca5a2734f3071c1d724eab843e39e1b06d429a3bc121650a635d2e96cc5d1b2' 
  AND token = 'SFKjpZRR9KSVxKlxFz9wBaV7FPnfAgf7cNIiGgLLnjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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