SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9146c67a6e71cf0bc6568334efb30ebaca273c2bdc33ff2531f9ffb5a47be7c4' 
  AND token = 'RSooNcBLvT9uzSM0MqOwdhMdgIwomdNX+I6bwpDIv6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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