SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f5b45d2ae68c94496efd25b5ad773d4aa3f971da2a565719ffbd6c9959db2ce' 
  AND token = 'CXFEytIXSdXLQbLApCbl4kJIU3T5H7ATYN9u/52Chak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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