SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3845a150b5e1803cd3a824b9572236dceac24a22ae2302885673ad88aab3c450' 
  AND token = 'l97cy7Mp2MCiIeJqBzig+Cly6D0Vq3l4FiJpecfryVI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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