SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bf916cbcaef0daae492258c0da29d4fa0227421b88a41232d16464efff30b39' 
  AND token = 'JZb3aS4zB/fJXzvxldGN2E3dPnYPFQlh2w6oR7RTJDc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}