SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09674a78c565dc4e578b38154d355bcddff3eb4e4a35549afdcdca217a8a1021' 
  AND token = 'SZioHEiyIqeCJttpS8huPZQjipoC/JUUfipbNTtpRBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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