SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '20ce19e2ccbebdd59a6a6da81b1ea994839b0d3c9770b71f51541cd353ba04a3' 
  AND token = 'uhz1537Jzr2KUjvVqH1gcBY2m4JGEqwp4gtmRm7AAt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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