SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bc5d97e284f61c6ce539804b8f53ac12c50721d37ba51fe45828dae3348e724' 
  AND token = '3/ASh8GOGhzsQVdpK89Q/CmPKQWEJwVwOM2NTOu9sqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}