SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '999a4dddaa4dcaf7df413bea10c78d295b9208754348820912f3a1d8d3d5c8c6' 
  AND token = 'ID8SRE2loh9hCuSvG0ufmcvhEyljjidbUG7TtHKqGck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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