SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ca6801b16d5da3959c35dfaa47e63985d7279020352c1dc1f918f6f56ab231a' 
  AND token = 'HIqQhK5ZbBv+FcJahDRJ5S3YoXpmOvXxvEgymiXQJuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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