SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6da269172a3269606a6cc895df996e8a69b7889388b238fbfb2ab4ca60641e21' 
  AND token = 'eczojK5ANj7weaVf9DdRpoEu2yWUVqT8gRe0y00h3jY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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