SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3e9f9331faf9515a2f354cc351292dfb665cdd59a5ce4c0e4146f0936846cdc' 
  AND token = 'i28bU3dOdYxvHeZdAwLOVXfNycX0DHppSjUhZYVOm50=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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