SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '543f55125e281c8fedf0958bb819f5668a91606d32078f6e98820549493f5e2e' 
  AND token = 'ZWhHd22bYiuGB6nuEfub7WkrLf7rBfSqP3k2tLWSIHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}