SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '1df07b071ceff2811379a24fad18a457b0fb42153951a31fb5ad707be865a3c0' 
  AND token = 'TxSIw7F16kzE1zgnf2jbJD7NlciDaganHQFwu5PLnEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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