SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac9334e4f8f7de544c9bf70500490613e61cd3e4ac63c5464951295854d06c9b' 
  AND token = 'tM8sYo20KgsfZHqspkVgSA+dHmXUShhJ8BAvkY1+6BY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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