SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '126273b9bc07d180e01d2b9530d2b091a02fbce13ee4a7f67f449ded1fdca39e' 
  AND token = 'BXdVFzq5LWKDnYpNKGLoIP7WtPobTIyFGairFBvSxfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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