SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90a3a529959c8a26d481c9f89685f794af4d1035e8c1ea01eee254eeecad4366' 
  AND token = 'hgCTCy0YsL3VavBq+bi5stZ7OsUmwC97zXasgngaYxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00065

JSON explain

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