SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '496f6ffc066a1c1d87f65fd2cb7fd24f79677e71a57454971d38b3993729f4e6' 
  AND token = 'PYZfiL6zWku+XQIMdPaBGSPnZSMBBKQRBgUzZzhySr0=' 
  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"
    }
  }
}