SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bcd3cdc9207956711deb05138c8c66b079e576df3161ffb94a4bca43681d7f2' 
  AND token = '5HIXJWMiKfHfQtd9q17vBm+zKVZHPsFeTwG7AM8KO4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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