SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5924ddc651533854e6ab0637733d05df5483eadb1d7a5b8e5a7e011aefa84362' 
  AND token = 'jcpdKXhnyTJfPoUGbzL+VFf19UP8NV0MmbnvuS1wpXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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