SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bf2c6780bdc58d96ea06a809b04b4335ed25524683f1672f8b3e0b296404d68' 
  AND token = 'ghSKyALQ2njjHw5L543m9MSUyCkAyMD53nJj1VlBmT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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