SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fb73e260a076dadf26e279a5110571e9ea2b40f859a6734797f2ef86ab747bd' 
  AND token = 'UF8jDsCyfczkG/cosMaKExHlPQrHGbwbscCjHVUNt1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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