SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be69b9067fa283af7d208a5988be0b72d09a7e03b7bb0abf8df04d995dfdf816' 
  AND token = 'jEn6AEq8hlSPyqT9+xqaw3SIUtFwa/VOST2mAmK5VAw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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