SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b63f39b03d64542cf837f5604897dbdad8ad466ea179763c0d18baf647ecfc9b' 
  AND token = '2dYoNhlmxPuNj0W5lczQmI1IBptFwacBZB5l80VYgRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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