SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8eeb9d05a451ef3bf0a96fe79582612827fa51e80e81f3e58fa32e464826f7fb' 
  AND token = '9MHjRH2iQXpe8vFOUEFAyoUh/dXsAWevGvLTmsimjnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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