SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df0fb01b609c007ebc333a813fe97cf2da16172afbe24b89e6c83c3d7d5914e4' 
  AND token = '4tHNwYUSYG8j09KEMZJB9rJaL/pNmlnYbFJMtSH7+QA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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