SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f02c9ad5eacbb4c748e247ad469e1cd6fdec09cd0919282afdbde71a635f42e' 
  AND token = 'LopkuBUtbShZlPkeDYqrkWW0xbQ4zzUYAecv2oEfOXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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