SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fe8d4fa4b33805d2fe2d9062ebea47603777c8d1868a6fa124a6d4f4bea281d' 
  AND token = 'Hz21f9d0DG4LolzcZTqN0WfIT6RHLtJcdHiyLxrURw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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