SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be76a52f3bc86da2eb2a50412d847277957aefb80ec02d950fda89b1a5f721ae' 
  AND token = '+Hh9ToqKrvGD13xgwlPaKVziCT2OlGeKjLre4nMaUzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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