SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84df354d07f6089db7046f7ed038b086d762cde4818d1c331369dfb351cba477' 
  AND token = 'T8yrdKKqXKkuMwJLfI5GD9DCEpbvykAzBPvwaDIRkoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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