SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '864d69af96bfbaa3f692168310f5d8538a18a58969666fe43d5a324fad6fed11' 
  AND token = 'vIQo7YyO74yaGNHMzQUij++SZvCpND7TFQcGqb4I2W0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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