SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de6a141667639c2e4f2b76f4db3a0a13be37f4d83e6ff294692122ee9e418d4d' 
  AND token = 'VzeD392zQxSdRXWm/ztTsiSNUywFYPCGB6ztl7itJ00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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