SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1538276456a0df6c0a8e962b55180c2fcfefc726fc5b49e026d4becce1e990e' 
  AND token = 'l5vmQFxbzfe3nxhHivuroexCRD3ucUNNDASzqQhTBoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00127

JSON explain

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