SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb456c22546d5a260d8dd17394d63859e2b9c19258f3f92f0b1e95013c75b3c3' 
  AND token = 'yN1gVVNU2aqyOnYUfciIpJxOaeCr4uUGVbCdTVrmqZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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