SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd79819fa8d8a692b264834cf766d53349d9b87153ed38b8038fc31d0d4ead227' 
  AND token = '84dDtzA471FmMqZI0lszfXfx4EPf89OlkfI16Y0z4oo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00063

JSON explain

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