SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d187be62509c3f8307288ad170a9fc80029a42d2573be494f31e17222ebcb99' 
  AND token = 'XBlPpySz8XV8/IAiGolzYaNXBU6Dnt4YB/z1KwtQDVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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