SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5842e3ae3ec5d385c4e18f4fd1d0d92af85b9be3f24f1272fcfe8212d6ab92f8' 
  AND token = 'J154ns6WYKDybRFhUjxhJGOe/NqBci1CsgzVGsM431w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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