SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '358095c83ba617078726716e68be9d7c23f6b02b17e996bfbe85c047b6360264' 
  AND token = 'eU/SxwQQvHOjVdxUpSSMjxYz2HhQdw+AM584SDQnaNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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