SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '342aba441f258a27edcdfcc9cf9680cff6826bf88d259e33c02848b31c9b8991' 
  AND token = 'qyYYDS+MVZEPIIAK4MFYJb1AWUke6hncPPGR9DyVYfE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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