SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37a6edf1fe64501c304e500549614506ebad1bbf65e28253b99472db1077f8fb' 
  AND token = 'BXZkA3u7qG2gZRsERFVQ9cDtWlgLQiPabFhjNkhtUJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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