SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8c2b196095373363c83dbce7af6f1911e035042c5bb6a9ebf653145b7ff0408' 
  AND token = 'asW1njE/bJLkKufKMkZ2zMq0+GlbZ6+yRdDqvW0X81w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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