SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8123a6a547f14654093ea783f01694e907dd6f40bcd194f728bc0e090750b535' 
  AND token = 'Kp5ptfY1CRz9u1o68UGCB9YmZCC3YZbS/pqFJaXEPVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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