SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1401a7623744cc3b6456eaaf2cd2f32dcae739c7afd9df9db69dc2af6d36cf51' 
  AND token = 'dLaTDMwx0ARXGtv5ZY0MqlNh/7RFeh3EsuR/F1ArOqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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