SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3e220cf05d4423526cf8a7c31866ee3715da530e12279a4d2b65680c61d1b96d' 
  AND token = '2aH1iVYtGK65ZZ8rzHRi0db+WlwWmdehMfOBVuejVkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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