SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17738377a5c850e3e2d075b9ff3749df4aedeb176902ccbc71982603b9856b14' 
  AND token = 'M9Q5ort6Uyfl7md3DpOImwjIbtwgQw6HdKDcEziUzUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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