SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcf89025bc4903674676c90b18f39ed7492199ed733f7ec3887b1bd72bdfca3e' 
  AND token = 'zzR49MJO2N+usWtZZj2D+AwV4cVWCXJ+6bffY6l5mKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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