SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bef5c57bf90c9393241058663ad40a736af4c04879bf2a47967241d6ae6a99ad' 
  AND token = 'BwRlmRfjcKfzoeVVpTByoyXBRWy129unGTKabdN1sQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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