SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d44cb72d16ab3ceab0acb4c199fe5b246f9792720ee058e58b79f2a8754e840' 
  AND token = 'sHcxKSkzF54cuodxoH8g8CpxEiiRwEkbVIpogKsk97w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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