SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12278f7f8fa4fc07a99a6dfc421bcee3f7f464e623f79e967d299d22d815b8c1' 
  AND token = 'D+PmiCMnO7iIf78/xZaj+jkm8XhYjzPvCzrEVDpPc14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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