SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '655ac28d9f01be942e7aa0a8827d6bdc6d069206dbeff13c602c40516c958857' 
  AND token = 'jctu4oDjL8RRfoXQkigklfFvL/GGJwO4/OwMEmf+yPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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