SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88d928291f9acc6fb65970253e1951d1fdb38d9e81623c24a7bb043e73b268c2' 
  AND token = 'dASVMVtXgqjg5UdP4vMAEUc8kCMzhZPM2oK6DddlyF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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