SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cce21a3228341bae528c1258181f84c60dfba6396a796db5f69ee7b640054961' 
  AND token = '2WABQYV4K3BNFAPqwmrmK/HDs5B6NMg4KVFzfnHJnPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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