SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aff59408bd38fc02d47a41435d0512f258fbfca2de09d16551b25edfce46a744' 
  AND token = 'yCGmtKVWn71TIx26lDWP9zVkqz9FdSp2o3dpAliegzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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