SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d890a2c68df0353651a6202549e814aac0ffa142e76927fb5480f1af80663b2' 
  AND token = 'IMC2QYKr6q0DFuXVuDjlaUYfxJEfqC4KMH2gLA2S/NI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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