SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c868b2d7904d67d092cbbfc34e43d43d5fb67f0087c9e4cd6436941d2f60d6e9' 
  AND token = 'cklhiJKwDtfmovun4RznFHlpCb8+r/TBjK2CJ2y2s/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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