SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '9c5667a0f13a7eb57d7f3520b0f4b36d617386e208d2af8d3b18e009b5e45838' 
  AND token = '2fxWxkNbwc71VqCNQPPMtxIleRsaOnpqK+4G6f9h2GY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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