SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a5d6bf8b893c3d32176e02bf4a7fedc0bec634e858aac868ea8d74fa4216261' 
  AND token = 'ym7JDlU93VrA8m0YSx76wPxtM7QjCCTnUANgkslcSz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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