SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15bde170c0b924eb404165fe0f18e2547d0054ed088747d1c2599ea4e2142a22' 
  AND token = 'hY0xNN1xhKjWhWo8AAWzZ+W8v1s4GL/FjHn6HuZCkdc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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