SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3f9c47e082bc12f69384a42e6fcde7dda40f3104617779b8593032836f87a34' 
  AND token = 'MEw75U3wr5olJuhaWIQr7A/ktotNLimVpHVYfyqHO2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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