SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f27f68ebe6b48fa3a6f3629f1e579089b49fdc7d10c8b77585e41fc568a4607' 
  AND token = 'eO0Pdk8NtZ84k88Rf5Dx8gaRC92E8vFgaTNOiwJuGcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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