SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c85ca52beb9d62acad18c7635c423e77f1bc6808fb2555db0a1e4bdac387624' 
  AND token = 'wCuYJlResk0Wn0GM5Olw+nm9AykcCZWOMoTPAGxsVkM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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