SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f072bd75d1d3be88f8b402754459f7af2847cb0075b49b0295ea958f93e64948' 
  AND token = 'mRu130CZMwQiQg2UG+MQUcnLoPzvey0zefgaqXwU9UI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}