SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ec4d8c20e4bc26380de61a7538945704bbd1486bf23369a38b1f159b387f0f6' 
  AND token = 'Jmd0ApLr/ZJKi948qBbzdlmmwwPARkgrmB+X7Zo/AOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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