SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de6ea1efde9360822152111fa3a4a4606984fa6de480439cd25800695d0e5067' 
  AND token = 'T/Muhgj8fAimbKvWobcLeSJDQl/kTzf4rGxvhygLXyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00092

JSON explain

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