SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2cd76e5572924dd9948d52f917557b2361da9283247ef1af52c7b637c9c325e' 
  AND token = 'WW/4EHvewLPw8LHw0GcjvOZR4GpfsJBm05pfg/eZ3MU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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