SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '988bf9fabbf3d22a4aba3ea59658b49bb7437d2fd4f0931bccb6fd545a2b9d71' 
  AND token = 'H+Pnz58vaOkcLQW0pBmFsergV1yogX14pAfPJ/IHUtQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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