SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49547a9ae7238f17d76d7174d75e9570a1f6e2e3e4fc84eb5929d38738002a08' 
  AND token = 'fBWISMqvu822iFE76F+4koLzU5wWAv7xsfD7a+GKjF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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