SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b18b261e85d9418465798cb2815c5d9b88eb00aa6cec41f46a5301db07b594a' 
  AND token = 'Ui8BOq0EZ2AdcoJEW+r4a/LuQZ+6t5vYfwihvH7GQqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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