SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3642f68366d9b00a31b910f205e22b9baa3bad6e5f37794410fd17547315ed72' 
  AND token = '8E/gYDGfMqMStuN7VhQjzTCOBKbExuowB4uQ3OPmqT0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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