SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3db19c48dd1cd73031f30eee82bbd17eb52851c819a26d9776cba02454e9912d' 
  AND token = '8N5QAEKw1E4oQqWEd0kXVKAWWkgCHNZCxv7Q8tosR3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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