SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '719f369effe0d4e2341d6884b9379bb1c273b721db44a7b253987e49717507b1' 
  AND token = 'tKYxQSiuVJNij/1EqVK7tP8FDSpvI1G+EhmOcnrcDwY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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