SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4dcc71d9d324e7506f43c66aa0301f863479725644e9edec21c5d7e22dea0560' 
  AND token = 'NnNZTaHbvUpwxzsJD10bfGbwPAPNCM81+oOmnWirlVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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