SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43d3860541498c01a39860e4cf87413345beef3c873483194e290487e4597a72' 
  AND token = 'TaVkD/m0drPl1d8gaR2+K1OkiqOEA8G1ulDL462phUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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