SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e861574718030d282c4e7cb77322dd54bbdb7b9dfb5b2efc73b34e3245704493' 
  AND token = 'dvqwCzt5aSogtjO/NvdgMfqgnUZdHDFrPJg614uK4gc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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