SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '429292fac8bc42408663cd303286eb31298ee9ef4878078d7bbf063ad21ecc91' 
  AND token = '7J8vZWeg9aDN1PeTEgS/hStuak3euKck7jRpdvafGWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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