SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90107836cca43ff2a8ad8c5c0dd097c5415279be2a02f6b28b6ecf72cbebf6c9' 
  AND token = '3CWcxgMmvMyLc8DknPpyLAsKKImPrVcQX+ucdKfYtN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}