SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ec8ab560392e5a43eb4fd4bae77cd269cbe0aa93c3ee6bfda612a000041f4ce' 
  AND token = 's8Wp/XblJxUjpqU1IBgg3ZeForqSG2yLeKfg4CuI1ME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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