SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79c48597bb65778b29e8b6a2bfdb1f635a0ad6e00f20427b19e416b3afc23506' 
  AND token = '0ztchePkgfZ5KmzDECD/2b+NodcJphqIwwhjbBYYZMA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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