SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f4907d902b890a0baf767c060964a709483a932fcbc3cac8bccdbe0d7e320a1' 
  AND token = 'AIiym5CkjWOnJu/ENz9ul8eAs6/tqkzPFfGj3kR/+q0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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