SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '639a357e1e3e1710eb5f530fd14f6a6de2af6cfe57a1604fe800bf4af45efdaa' 
  AND token = 'xjmLAWl9Ll2nDc1PB1hdeaA4m1f/hafntuXx0wcKEMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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