SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dc13fb68eb4d5a55890ad083bb50cdb29bc7c994179dba9c233ffc0edb7d0d4' 
  AND token = '9IZ/nQRK4jB0JHbXPYVZYPGK5ezyUPQwNzwgT9pYafs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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