SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '21d14723611116e06c861d1648c3353cc3b61330c85c061cb5468c75b7577cbc' 
  AND token = 'V2dWBInCUl5NS9f/o1y72UVReWqoRbpQ8oc+6F1lrhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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