SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fab0574503992d36a0a8460e260c84ddc483499b30d5982c916ad4abe22799b8' 
  AND token = 'IwfmB6hIkubdLf2l9s+/6asSWyePocsfuJpUzhAjunI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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