SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e38f77f95e436b8c9182bd76e0fc8056a59105386fb68489aaf6cf0ce546b56' 
  AND token = 'GqMkX01wDa56hksZRXsXqglznvlP99rjx/ulAC+jqGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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